Last spring frost
May 16
Frost Dates for Acequia, ID
First fall frost
Oct 1
Growing season
136 days
Hardiness zone
6a
In an average year around Acequia, ID, the last spring frost (32°F) is about May 16 and the first fall frost is about Oct 1, giving roughly a 136-day growing season. To be safe most years, wait until Apr 30 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 22 | Jun 3 | May 16 |
| Freeze (32°F) | Jun 5 | May 16 | Apr 30 |
| Hard (28°F) | May 19 | May 2 | Apr 16 |
| Severe (24°F) | May 3 | Apr 17 | Mar 29 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 22 | Jun 15 | Jun 10 | Jun 6 | Jun 3 | May 31 | May 26 | May 22 | May 16 |
| 32°F | Jun 5 | May 30 | May 24 | May 20 | May 16 | May 13 | May 9 | May 5 | Apr 30 |
| 28°F | May 19 | May 12 | May 8 | May 4 | May 2 | Apr 29 | Apr 25 | Apr 22 | Apr 16 |
| 24°F | May 3 | Apr 29 | Apr 24 | Apr 20 | Apr 17 | Apr 13 | Apr 9 | Apr 4 | Mar 29 |
| 20°F | Apr 17 | Apr 11 | Apr 6 | Apr 2 | Mar 30 | Mar 25 | Mar 18 | Mar 13 | Mar 6 |
| 16°F | Mar 31 | Mar 22 | Mar 15 | Mar 10 | Mar 7 | Mar 3 | Feb 28 | Feb 22 | Feb 14 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Sep 1 | Sep 15 | Oct 1 |
| Freeze (32°F) | Sep 13 | Oct 1 | Oct 16 |
| Hard (28°F) | Sep 30 | Oct 15 | Oct 30 |
| Severe (24°F) | Oct 10 | Oct 26 | Nov 8 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 1 | Sep 5 | Sep 8 | Sep 12 | Sep 15 | Sep 18 | Sep 21 | Sep 24 | Oct 1 |
| 32°F | Sep 13 | Sep 20 | Sep 24 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 11 | Oct 16 |
| 28°F | Sep 30 | Oct 4 | Oct 7 | Oct 11 | Oct 15 | Oct 17 | Oct 20 | Oct 24 | Oct 30 |
| 24°F | Oct 10 | Oct 16 | Oct 19 | Oct 23 | Oct 26 | Oct 28 | Oct 31 | Nov 3 | Nov 8 |
| 20°F | Oct 16 | Oct 21 | Oct 26 | Oct 30 | Nov 1 | Nov 5 | Nov 8 | Nov 13 | Nov 20 |
| 16°F | Oct 21 | Oct 28 | Nov 1 | Nov 6 | Nov 10 | Nov 15 | Nov 20 | Nov 25 | Dec 1 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Minidoka Dam, Id, about 5.6 miles away@if(!empty($station['elevation_ft'])), at 4,164 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Acequia, ID?
On average, the last spring frost (32°F) around Acequia, ID is about May 16. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 30.
When is the first frost in the fall?
The first fall frost around Acequia, ID typically arrives about Oct 1. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around May 16 on average, or Apr 30 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 136 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 83350 Planting calendar → Idaho frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026